Malignant melanoma presenting as an isolated pleural effusion

Isolated pleural effusion is a very rare presentation of malignant melanoma. A 46 year-old male patient presented to us with complaints of shortness of breath during the previous month. A contrast enhanced computed tomography (CECT) imaging scan of his thorax showed right-sided pleural effusion with the absence of any mass lesion or mediastinal lymphadenopathy. Cytology of his pleural fluid showed pigmented cells suggestive of malignant melanoma. Staining of the pleural fluid cells with immunohistological markers for melanoma (HMB 45 and S 100) were positive. An examination of his skin did not reveal any pigmented lesion, nor was there a past history of malignant melanoma for this patient. The patient responded well to therapy for malignant melanoma and has remained asymptomatic for the last year. This patient was diagnosed with a rare case of primary malignant melanoma of the pleura presenting as isolated pleural effusion.